Garrity D B, Zahler S A
Section of Genetics and Development, Cornell University, Ithaca, New York 14853.
J Bacteriol. 1993 Oct;175(20):6512-7. doi: 10.1128/jb.175.20.6512-6517.1993.
Most Bacillus subtilis tRNA genes have been isolated from lambda libraries by use of probes that hybridize to tRNA or rRNA sequences. None of those genes map to the region of the sup-3 mutation. By cloning of the sup-3 allele, a cluster of seven tRNA genes (the trnS operon) that had not been isolated by other methods was identified. In principle, this approach could be used to isolate at least one more predicted tRNA-containing operon in this bacterium. The trnS operon was shown to contain tRNA genes for Asn (GUU), Ser (GCU), Glu (UUC), Gln (UUG), Lys (UUU), Leu (UAG), and Leu (GAG). The sup-3 mutation was found to be a T-to-A transversion that changes the anticodon of the lysine tRNA from 5'-UUU-3' to 5'-UUA-3'. This result agrees with previous work that determined that the sup-3 mutation causes lysine to be inserted at ochre nonsense mutations.
大多数枯草芽孢杆菌的tRNA基因是通过使用与tRNA或rRNA序列杂交的探针从λ文库中分离出来的。这些基因中没有一个定位于sup-3突变区域。通过克隆sup-3等位基因，鉴定出了一组七个tRNA基因（trnS操纵子），这些基因是通过其他方法未分离到的。原则上，这种方法可用于在这种细菌中至少再分离出一个预测含tRNA的操纵子。trnS操纵子被证明包含天冬酰胺（GUU）、丝氨酸（GCU）、谷氨酸（UUC）、谷氨酰胺（UUG）、赖氨酸（UUU）、亮氨酸（UAG）和亮氨酸（GAG）的tRNA基因。发现sup-3突变是一种T到A的颠换，它将赖氨酸tRNA的反密码子从5'-UUU-3'变为5'-UUA-3'。这一结果与先前的研究一致，该研究确定sup-3突变导致在赭石型无义突变处插入赖氨酸。
